Fayette County is a county in the Commonwealth of Pennsylvania. It is located in southwestern Pennsylvania, adjacent to Maryland and West Virginia. As of the 2020 census, the population was 128,804. Its county seat is Uniontown. The county was created on September 26, 1783, from part of Westmoreland County and named after the Marquis de Lafayette. The county is part of the Southwest region of the commonwealth.
Fayette County is part of the Pittsburgh, PA Metropolitan Statistical Area. The southern border of Fayette County is the southern border of Pennsylvania at both the Pennsylvania–Maryland state line (the Mason–Dixon line) and the Pennsylvania–West Virginia state line.